Tension latch



April 29, 1958 sMlTH ET AL 2,832,446

TENSION LATCH Filed NOV. 13, 1956 m N N e 7 M O K i v M 4 Am United States Patent TENSION LATCH Lawrence D. Smith, Pacoima, and Franklin Sawyer, Canoga Park, Calih, assignors to Clark Hartwell, doing business as Hartwell Aviation Supply Company, Los Angeles, Calif.

Application November 13, 1956., Serial No. 621,867

Claims. (Cl. 189-35) This invention relates to tension latches, that is, to latches wherein a preselected tension is applied to the mating structures connected by the latch. Included in the objects of this invention are:

First, to provide a tension latch wherein complementary structures which are intended to assume a confronting relation may be drawn together and then secured in predetermined spatial relation or caused to exert a predetermined bearing pressure against each other, the latch components being placed under corresponding tension.

Second, to provide a tension latch which is arranged to mount flush in a surrounding structure and precurved or contoured so as to conform therewith, thus providing a latch which is particularly suited for aircraft use.

Third, to provide a latch of this type wherein one component includes a connecting link and a combination handle and catch element intended to engage a mating latch element set within a channel forming a part of the other latch component, the latch element being adjustable as to its position.

Fourth, to provide a novel latch-handle-releasing means which is adjusted in position upon adjustment of the latch element so as to maintain a predetermined coacting relation with the handle and catch element.

With the above and other objects in view, as may appear hereinafter, reference is directed to the accompanying drawings in which:

Figure 1 is a top view of the tension latch shown in its latched position with the surrounding structure in which it is mounted indicated fragmentarily;

Fig. 2 is a longitudinal sectional view through 22 of Fig. 1;

Fig. 3 is a similar longitudinal view with portions in elevation and showing the latch in its extended position prior to disengagement;

Figs. 4 and 5 are transverse sectional views through 4--4 and 5.-5, respectively, of Fig. 2. The tension latch comprises two mating units, one of which is contained in a housing 1 in the form of a longitudinal channel 2 having side walls 3 and a bottom wall 4. The upper margins of the side walls 3 are provided with laterally extending flanges 5 for attachment to a surrounding structure, such as the skin.

The channel 2 is provided with a transverse rib 6 having a screw-threaded bore extending longitudinally of the .channel which is arranged toreceive a screw-threaded latch shaft 7. One end of the latch shaft terminates adjacent an end of the housing 1 and is enlarged to form a head which receives a cross pin 8. The head of the latch shaft 7 may be slotted to receive a screw driver for the purpose of rotating the latch shaft and thereby adjusting the position of the shaft longitudinally with respect to the housing 1. A friction plug 9 may be set into thetransverse rib 6 so as to bear against the shaft7 and prevent accidental turning movement of the shaft.

' hold the lip 16 in ice The opposite end of the shaft 7 journals a block member 10 which is held on the shaft between a collar 11 and a washer 12. The blocklt) carries a transverse pivot pin 13.

A trigger lever 14 having parallel depending cars 15 is journalled by the ears 15 on the pivot pin 13. The trigger lever 14 projects rearwardly, that is, in a direction opposite from the cross pin end of the shaft 7 and forms a stop lip 16 adapted to underlie a deck or ledge 17 formed at the rearward end of the channel 2 between the top margins of the side walls 3. The forward end of the trigger lever 14 is disposed above the axis of the pivot pin 13 and forms a retainer lip 19 for securing a latch handle, to be described hereinafter.

The portion of the trigger lever 14 between the retaining lip 19 and the ledge 17 is so arranged that its upper surface is substantially flush with the surrounding surface of the structure in which the housing 1 is mounted. This portion of the trigger lever 14- may be provided with a screw driver slot 20 for the purpose of pivoting the trigger ever.

A spring 21 is wrapped about the pivot pin 13 and is provided with portions which bear against the underside of the collar 11 and the underside of the lip 16 so as to yieldable engagement with the ledge or deck 17.

The companion unit to the housing 1 and the-structure mounted therein includes a mounting plate 22 which is shown as being adapted for attachment under the skin of a structure which is intendedto be joined to the structure in which the housing 1 is mounted. The mounting plate 22 isprovided with depending lugs 23 which pivotally support a connecting or link lever 24 having an arm 25 extending under the plate 22 and a yoke arm 26 extending outwardly therefrom. The upper surface of the yoke arm 26 and the location of the arm 25 are such that when the arm 25 bears against the underside of the mounting plate 22 the upper surface of the yoke arm 26 is substantially flush with the surrounding structure. The width of the yoke arm 26 is such as to fit within the channel 2.

The yoke arm .26 is bifurcated at its extended end and includes depending lugs 27 which are provided with pivot pins 28 for the purpose of pivotally mounting a handle member 29. The handle member forms a catch arm 39 positioned to extend between the pivot pins 23 and the pivotal connection between the mounting plate 22 and connecting lever 24.

The underside of the catch arm 3% is slotted longitudinally to clear the latch shaft 7, and its extremity is provided with notches. 31 proportioned to engage the transverse extremities of the cross pin 2. t

The remaining arm of the handle member 2? forms a handle arm 32. which is proportioned was to fit between the side walls 3 of the channel 2 and extend to the trigger lever .14. 3

The upper surface ofthe handle member 29 is contoured so that it may be positioned .fiush with the surrounding structure. The rearward or extended end ot the handle arm 32 is provided with an offset 33 which is adapted to extend under the retaining lip 19 of the trigger lever 14. The underside of this extremity of the handle arm 32 is provided with cam lugs 3- which cam against the adjacent end of the trigger lever 14 so that the handle member 25 may be snapped intoan interlocking position relative to the trigger lever 14.

Operation of the tension latch is as follows:

The housing! is mounted in one of a pair of structures to be joined. Its upper surface, which is defined by the upper edges of the side walls 3, may be: contoured or curved so as to conform exactly to the surrounding 3 structure and be flush therewith. The mounting plate 22 is secured under'the skin surface of the structure to be attached in proper alignment with the housing 1.

Due to the pivotal axes supporting the handle member 29, the handle member may occupy a position substanitally at right angles to the housing 1 so that the notches'31 of the catch arm 30 may rest on the ends of the cross pin 8. Thereupon, the handle member may be pivoted clockwise from the position shown in Fig. 3 to the position shown in Fig. 2 until the handle member 29 is brought flush with the upper edges of the side wall 3, and in doing so the free end of the handle arm 32 is caused to snap under the retaining lip 19 of the trigger lever 14.

It will be observed that the two structures in which the mounting plate 22 and housing 1 are secured may be drawn a substantial distance toward each other by the pivotal action of the handle member 29. The final relative position of these two structures may be adjusted by turning the latch shaft 7 so as to advance or retract the position of the cross pin 8. In making this adjustment of the latch shaft 7, the trigger lever 14 is also moved longitudinally so that for all adjusted positions of the latch shaft 7 the retaining lip 19 of the trigger lever 14 is maintained in proper relation to the extremity of the handle arm 32. In order to permit substantial adjustment of the latch shaft 7, appropriate clearance is provided between the flush surface of the trigger lever 14 and the adjacent end of the deck or ledge 17.

In order to release the latch, it is merely necessary to press downward on the trigger lever 14. While this may be done manually, the presence of the screw driver slot 20 permits the application of additional force, so that the spring 21 may be relatively strong and thus prevent any accidental disengagement from the trigger lever 14 from the handle arm 32.

It should be noted, however, that by reason of the fact that the retaining lip 19 of the trigger lever 14 is directly abovethe axis of the pivot pin 13, the handle member 29 cannot exert a force which would tend to pivot the trigger lever 14.

It should also be observed that when the tension latch is in its secured position, as shown in Fig. 2, the axes defined by the pivotal connection of the connecting lever 24 with the mounting plate 22 and with the handle member 29 and the pivotal axis defined by the notches 31 and cross pin 8 define approximately a common plane so that any tensional loads applied between the mounting plate 22 and housing 1 exert little or no turning moment on the handle member 29.

In order to facilitate movement of the handle member 29 to a position capable of manual engagement upon release of the trigger lever 14, the trigger lever may be provided with forwardly directed arms 35 which engage the underside of the handle arm 32 as the trigger lever 14 is moved to its extreme tilted position, such as shown in Fig. 3.

While a particular embodiment of this invention has been shown and described, it is not intended to limit the same to the exact details of the construction set forth, and it embraces such changes, modifications, and equivalents of the parts and their formation and arrangement as come within the purview of the appended claims.

What is claimed is:

1. A tension latch, comprising: a housing adapted to be secured in a structure to be connected to a mating structure, said housing defining a channel having a latchshaft mounting means therein; a latch shaft screwthreadedly connected to said mounting means for preset adjustment longitudinally of said channel and having an element at one end engageable by a catch arm; a mounting member adapted to be secured in a mating structure at a location confronting said catch arm engageable element; a link lever pivotally connected to said mounting member; a handle member pivotally connected to said link lever and having a catch arm engageable with said element, said catch arm movable from a position in angular relation to a plane defined by the pivotal axes of said link lever and 'handle member to a position approximately coinciding with said plane to engage said catch arm with said latch shaft element and pivot said catch arm in a direction toward said mounting member thereby to draw said mounting member and housing together, said handle member including a handle arm movable into a position longitudinally of said channel; and means for securing said handle arm in said position.

2. A tension latch, comprising: a housing adapted to be secured in a structure to be connected to a mating structure, said housing defining a channel having a latchshaft mounting means therein; a latch shaft screwthreadedly connected to said mounting means for preset adjustment longitudinally of said channel and having an element at one end engageable by a catch arm; a mounting member adapted to be secured in a mating structure at a location confronting said one end of the latch shaft; a link lever pivotally connected to said mounting mem: ber and extendable therefrom into overlapping relation with said latch shaft; a handle member pivotally connected to said link lever and having a catch arm engageable with said element, said .catch arm movable from a position in angular relation to a plane defined by the pivotal axes of said link lever and handle member to a position approximately coinciding with said plane to engage said catch arm with said latch shaft element and pivot said catch arm in a direction toward said mounting member thereby to draw said mounting member and housing together, said handle member including a handle arrn movable into a position longitudinally of said channel; and a retainer lever pivotally connected to said latch shaft remote from said catch arm engaging element for longitudinal movement in said channel with said shaft, said retainer lever being engageable with said handle arm to secure said handle arm in said channel.

3. A tension latch, comprising: a mounting member; a handle member pivotally connected with the mounting member and having a latching means; a housing; a latch shaft longitudinally adjustable in said housing and having at one end a latching element engageable with said latching means to secure said mounting memher and housing in a relation determined by the adjust ment of said latch shaft; and means carried. by said latch shaft and longitudinally adjustable therewith. for engaging said handle member to hold said latch means and element in engagement,

4. A tension latch, comprising: a mounting member; a link lever pivotally connected to said mounting member; a handle member pivotally connected intermediate its ends to said link lever to form a latching arm and a handle arm; a housing; and a latch shaft longitudinally adjustable in said housing and having at one end a latching element engageable with said latching arm to secure said member and housing in a relation determined by the adjustment of said latch shaft; said handle member movable between a release position in angular relation with a plane defined by the pivotal axes of said link lever and handle lever and a locking position wherein the connection between said latching arm and latching element is approximately coplanar therewith.

5. A tension latch, comprising: a mounting member; a link lever pivotally connected to said mounting member; a handle member pivotally connected intermediate its ends to said linklever to form a latching arm and a handle arm; a housing; a latch shaft longitudinally adjustable in said housing and having at one end a latching element engageable with said latching arm to secure said member and housing in a relation determined by the adjustment'of said latch shaft; said handle member movable between a release position in angular relation with a plane defined by the pivotal axes of said link lever and handle lever and a locking position wherein the connection between said latching arm and latching References Cited in the file of this patent element is approximately coplanar therewith; and a trigger lever carried by said latch shaft and longitudinally UNITED STATES PATENTS movable therewith, said trigger lever being engagcable 2,653,842 Love Sept. 29, 1953 with said handle arm to retain said handle arm in its 5 2,712,955 Andrews July 12, 1955 locking position. 2,714,032 Summers July 26, 1955 

